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Augustijnen H, Bätscher L, Cesanek M, Chkhartishvili T, Dincă V, Iankoshvili G, Ogawa K, Vila R, Klopfstein S, de Vos JM, Lucek K. A macroevolutionary role for chromosomal fusion and fission in Erebia butterflies. SCIENCE ADVANCES 2024; 10:eadl0989. [PMID: 38630820 PMCID: PMC11023530 DOI: 10.1126/sciadv.adl0989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024]
Abstract
The impact of large-scale chromosomal rearrangements, such as fusions and fissions, on speciation is a long-standing conundrum. We assessed whether bursts of change in chromosome numbers resulting from chromosomal fusion or fission are related to increased speciation rates in Erebia, one of the most species-rich and karyotypically variable butterfly groups. We established a genome-based phylogeny and used state-dependent birth-death models to infer trajectories of karyotype evolution. We demonstrated that rates of anagenetic chromosomal changes (i.e., along phylogenetic branches) exceed cladogenetic changes (i.e., at speciation events), but, when cladogenetic changes occur, they are mostly associated with chromosomal fissions rather than fusions. We found that the relative importance of fusion and fission differs among Erebia clades of different ages and that especially in younger, more karyotypically diverse clades, speciation is more frequently associated with cladogenetic chromosomal changes. Overall, our results imply that chromosomal fusions and fissions have contrasting macroevolutionary roles and that large-scale chromosomal rearrangements are associated with bursts of species diversification.
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Affiliation(s)
- Hannah Augustijnen
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Livio Bätscher
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Martin Cesanek
- Slovak Entomological Society, Slovak Academy of Sciences, Bratislava 1, Slovakia
| | | | - Vlad Dincă
- Ecology and Genetics Research Unit, University of Oulu, 90570 Oulu, Finland
| | | | - Kota Ogawa
- Faculty of Social and Cultural Studies, Kyushu University, Fukuoka 819-0395, Japan
- Insect Sciences and Creative Entomology Center, Kyushu University, Fukuoka 819-0395, Japan
| | - Roger Vila
- Institut de Biologia Evolutiva (CSIC-Univ. Pompeu Fabra), 08003 Barcelona, Spain
| | - Seraina Klopfstein
- Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Life Sciences, Natural History Museum Basel, 4051 Basel, Switzerland
| | - Jurriaan M. de Vos
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Kay Lucek
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
- Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
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2
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de Oliveira TD, de Freitas TR. Investigating the evolutionary dynamics of diploid number variation in Ctenomys (Ctenomyidae, Rodentia). Genet Mol Biol 2024; 46:e20230180. [PMID: 38315881 PMCID: PMC10842476 DOI: 10.1590/1678-4685-gmb-2023-0180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/22/2023] [Indexed: 02/07/2024] Open
Abstract
Contrary to predictions from classical hybrid sterility models of chromosomal speciation, some organisms display high rates of karyotype variation. Ctenomys are the current mammals with the greatest interspecific and intraspecific chromosomal variation. A large number of species have been studied cytogenetically. The diploid numbers of chromosomes range from 2n = 10 to 2n = 70. Here, we analyzed karyotype evolution in Ctenomys using comparative phylogenetic methods. We found a strong phylogenetic signal with chromosome number. This refutes the chromosomal megaevolution model, which proposes the independent accumulation of multiple chromosomal rearrangements in each closely related species. We found that Brownian motion (BM) described the observed characteristic changes more thoroughly than the Ornstein-Uhlenbeck and Early-Burst models. This suggests that the evolution of chromosome numbers occurs by a random walk along phylogenetic clades. However, our data indicate that the BM model alone does not fully characterize the chromosomal evolution of Ctenomys.
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Affiliation(s)
- Thays Duarte de Oliveira
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Animal, Porto Alegre, RS, Brazil
| | - Thales R.O. de Freitas
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Animal, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil
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3
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Zhang DQ, Liu XY, Qiu LF, Liu ZR, Yang YP, Huang L, Wang SY, Zhang JQ. Two chromosome-level genome assemblies of Rhodiola shed new light on genome evolution in rapid radiation and evolution of the biosynthetic pathway of salidroside. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:464-482. [PMID: 37872890 DOI: 10.1111/tpj.16501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 10/25/2023]
Abstract
Rhodiola L. is a genus that has undergone rapid radiation in the mid-Miocene and may represent a typic case of adaptive radiation. Many species of Rhodiola have also been widely used as an important adaptogen in traditional medicines for centuries. However, a lack of high-quality chromosome-level genomes hinders in-depth study of its evolution and biosynthetic pathway of secondary metabolites. Here, we assembled two chromosome-level genomes for two Rhodiola species with different chromosome number and sexual system. The assembled genome size of R. chrysanthemifolia (2n = 14; hermaphrodite) and R. kirilowii (2n = 22; dioecious) were of 402.67 and 653.62 Mb, respectively, with approximately 57.60% and 69.22% of transposable elements (TEs). The size difference between the two genomes was mostly due to proliferation of long terminal repeat-retrotransposons (LTR-RTs) in the R. kirilowii genome. Comparative genomic analysis revealed possible gene families responsible for high-altitude adaptation of Rhodiola, including a homolog of plant cysteine oxidase 2 gene of Arabidopsis thaliana (AtPCO2), which is part of the core molecular reaction to hypoxia and contributes to the stability of Group VII ethylene response factors (ERF-VII). We found extensive chromosome fusion/fission events and structural variations between the two genomes, which might have facilitated the initial rapid radiation of Rhodiola. We also identified candidate genes in the biosynthetic pathway of salidroside. Overall, our results provide important insights into genome evolution in plant rapid radiations, and possible roles of chromosome fusion/fission and structure variation played in rapid speciation.
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Affiliation(s)
- Dan-Qing Zhang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
| | - Xiao-Ying Liu
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
| | - Lin-Feng Qiu
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
| | - Zhao-Rui Liu
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
| | - Ya-Peng Yang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
| | - Long Huang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
| | - Shi-Yu Wang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
| | - Jian-Qiang Zhang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710119, China
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Pazhenkova EA, Lukhtanov VA. Whole-Genome Analysis Reveals the Dynamic Evolution of Holocentric Chromosomes in Satyrine Butterflies. Genes (Basel) 2023; 14:437. [PMID: 36833364 PMCID: PMC9956908 DOI: 10.3390/genes14020437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
Butterfly chromosomes are holocentric, i.e., lacking a localized centromere. Potentially, this can lead to rapid karyotypic evolution through chromosome fissions and fusions, since fragmented chromosomes retain kinetic activity, while fused chromosomes are not dicentric. However, the actual mechanisms of butterfly genome evolution are poorly understood. Here, we analyzed chromosome-scale genome assemblies to identify structural rearrangements between karyotypes of satyrine butterfly species. For the species pair Erebia ligea-Maniola jurtina, sharing the ancestral diploid karyotype 2n = 56 + ZW, we demonstrate a high level of chromosomal macrosynteny and nine inversions separating these species. We show that the formation of a karyotype with a low number of chromosomes (2n = 36 + ZW) in Erebia aethiops was based on ten fusions, including one autosome-sex chromosome fusion, resulting in a neo-Z chromosome. We also detected inversions on the Z sex chromosome that were differentially fixed between the species. We conclude that chromosomal evolution is dynamic in the satyrines, even in the lineage that preserves the ancestral chromosome number. We hypothesize that the exceptional role of Z chromosomes in speciation may be further enhanced by inversions and sex chromosome-autosome fusions. We argue that not only fusions/fissions but also inversions are drivers of the holocentromere-mediated mode of chromosomal speciation.
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Affiliation(s)
- Elena A. Pazhenkova
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Vladimir A. Lukhtanov
- Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia
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Bastide H, López-Villavicencio M, Ogereau D, Lledo J, Dutrillaux AM, Debat V, Llaurens V. Genome assembly of 3 Amazonian Morpho butterfly species reveals Z-chromosome rearrangements between closely related species living in sympatry. Gigascience 2022; 12:giad033. [PMID: 37216769 PMCID: PMC10202424 DOI: 10.1093/gigascience/giad033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 02/13/2023] [Accepted: 05/12/2023] [Indexed: 05/24/2023] Open
Abstract
The genomic processes enabling speciation and species coexistence in sympatry are still largely unknown. Here we describe the whole-genome sequencing and assembly of 3 closely related species from the butterfly genus Morpho: Morpho achilles (Linnaeus, 1758), Morpho helenor (Cramer, 1776), and Morpho deidamia (Höbner, 1819). These large blue butterflies are emblematic species of the Amazonian rainforest. They live in sympatry in a wide range of their geographical distribution and display parallel diversification of dorsal wing color pattern, suggesting local mimicry. By sequencing, assembling, and annotating their genomes, we aim at uncovering prezygotic barriers preventing gene flow between these sympatric species. We found a genome size of 480 Mb for the 3 species and a chromosomal number ranging from 2n = 54 for M. deidamia to 2n = 56 for M. achilles and M. helenor. We also detected inversions on the sex chromosome Z that were differentially fixed between species, suggesting that chromosomal rearrangements may contribute to their reproductive isolation. The annotation of their genomes allowed us to recover in each species at least 12,000 protein-coding genes and to discover duplications of genes potentially involved in prezygotic isolation like genes controlling color discrimination (L-opsin). Altogether, the assembly and the annotation of these 3 new reference genomes open new research avenues into the genomic architecture of speciation and reinforcement in sympatry, establishing Morpho butterflies as a new eco-evolutionary model.
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Affiliation(s)
| | - Manuela López-Villavicencio
- Institut de Systématique, Evolution et Biodiversité (UMR 7205 CNRS/MNHN/SU/EPHE/UA), Muséum National d’Histoire Naturelle–CP50, 75005 Paris, France
| | | | - Joanna Lledo
- GeT-PlaGe, Bât G2, INRAe, 31326 Castanet-Tolosan Cedex, France
| | - Anne-Marie Dutrillaux
- Institut de Systématique, Evolution et Biodiversité (UMR 7205 CNRS/MNHN/SU/EPHE/UA), Muséum National d’Histoire Naturelle–CP50, 75005 Paris, France
| | - Vincent Debat
- Institut de Systématique, Evolution et Biodiversité (UMR 7205 CNRS/MNHN/SU/EPHE/UA), Muséum National d’Histoire Naturelle–CP50, 75005 Paris, France
| | - Violaine Llaurens
- Institut de Systématique, Evolution et Biodiversité (UMR 7205 CNRS/MNHN/SU/EPHE/UA), Muséum National d’Histoire Naturelle–CP50, 75005 Paris, France
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6
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Highly divergent karyotypes and barcoding of the East African genus Gonatoxia Karsch (Orthoptera: Phaneropterinae). Sci Rep 2021; 11:22781. [PMID: 34815452 PMCID: PMC8610994 DOI: 10.1038/s41598-021-02110-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 10/20/2021] [Indexed: 11/09/2022] Open
Abstract
East Africa is a hotspot of biodiversity of many orthopteran taxa, including bushcrickets. Gonatoxia Karsch, 1889 species are fully alate Phaneropterinae, which are perfectly adapted to the foliage of forests. We examined five species using combined cytogenetic and molecular data to determine the inter- and intraspecific genetic diversity. The variation in the diploid number of chromosomes in males ranged from 2n = 28 + X0 and 26 + X0 to 2n = 6 + X0. Fluorescence in situ hybridization showed from one to many 18S rDNA loci as well as interstitial sequences, especially in G. helleri. 18S rDNA loci coincided with active NOR and C-banding patterns. The isolation of populations of the species explains differences in the number of chromosomes (G. maculata), chromosomal polymorphism and chromosomal heterozygosity (G. helleri). Our molecular phylogeny based on the COI locus supported the monophyly of the genus Gonatoxia and separateness of the five examined species in accordance with their morphological features and chromosome numbers as well as the species' distribution.
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7
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El Taher A, Ronco F, Matschiner M, Salzburger W, Böhne A. Dynamics of sex chromosome evolution in a rapid radiation of cichlid fishes. SCIENCE ADVANCES 2021; 7:eabe8215. [PMID: 34516923 PMCID: PMC8442896 DOI: 10.1126/sciadv.abe8215] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Sex is a fundamental trait determined by environmental and/or genetic factors, including sex chromosomes. Sex chromosomes are studied in species scattered across the tree of life, yet little is known about tempo and mode of sex chromosome evolution among closely related species. Here, we examine sex chromosome evolution in the adaptive radiation of cichlid fishes in Lake Tanganyika. Through the analysis of male and female genomes from 244 cichlid taxa (189 described species with 5 represented with two local variants/populations; 50 undescribed species) and of 396 multitissue transcriptomes from 66 taxa, we identify signatures of sex chromosomes in 79 taxa, involving 12 linkage groups. We find that Tanganyikan cichlids have the highest rates of sex chromosome turnover and heterogamety transitions known to date. We show that sex chromosome recruitment is not at random. Moreover convergently emerged sex chromosomes in cichlids support the “limited options” hypothesis of sex chromosome evolution.
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Affiliation(s)
- Athimed El Taher
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Fabrizia Ronco
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Michael Matschiner
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
- Department of Paleontology and Museum, University of Zurich, Zurich, Switzerland
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Walter Salzburger
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Astrid Böhne
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
- Center for Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Bonn, Germany
- Corresponding author.
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8
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Grzywacz B, Warchałowska-Śliwa E, Kociński M, Heller KG, Hemp C. Diversification of the Balloon bushcrickets (Orthoptera, Hexacentrinae, Aerotegmina) in the East African mountains. Sci Rep 2021; 11:9878. [PMID: 33972656 PMCID: PMC8110521 DOI: 10.1038/s41598-021-89364-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 04/26/2021] [Indexed: 02/03/2023] Open
Abstract
East African mountains constitute a network of isolated habitat islands among dry savannah and are thus ideal for studying species diversification processes. This study elucidated the phylogenetic and phylogeographic relationships of all bushcricket species comprising the genus Aerotegmina. Our analysis indicated that large-scale climatic and topographic processes in Africa are likely to have driven speciation in this group, and revealed the cytogenetic traits of the species. Molecular phylogeny supported the monophyly of Aerotegmina and showed that the genus probably originated in the old Eastern Arc Mountains of Tanzania and Kenya. Two lineages were distinguished: small- and large-sized species with geographically distinct habitats. The underlying processes are thought to be eight dispersals, ten vicariance events, and one extinction event linked to repeated fragmentation of the African rainforest. Those processes, in conjunction with habitat change, probably also led to the spatial separation of the species into a northern clade with a diploid number of chromosomes 2n = 32 + X0 or 2n = 30 + neo-XY and a southern clade with a reduced number of chromosomes (2n = 28 + X0 or 24 + neo-X1X2Y). Karyotype analysis suggests that Aerotegmina is currently in the process of speciation.
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Affiliation(s)
- Beata Grzywacz
- grid.413454.30000 0001 1958 0162Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland
| | - Elżbieta Warchałowska-Śliwa
- grid.413454.30000 0001 1958 0162Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland
| | - Maciej Kociński
- grid.413454.30000 0001 1958 0162Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland
| | | | - Claudia Hemp
- grid.7384.80000 0004 0467 6972Department Plant Systematics, University of Bayreuth, Bayreuth, Germany
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9
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Grzywacz B, Skórka P. Genome size versus geographic range size in birds. PeerJ 2021; 9:e10868. [PMID: 33614292 PMCID: PMC7881720 DOI: 10.7717/peerj.10868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 01/10/2021] [Indexed: 11/20/2022] Open
Abstract
Why do some species occur in small, restricted areas, while others are distributed globally? Environmental heterogeneity increases with area and so does the number of species. Hence, diverse biotic and abiotic conditions across large ranges may lead to specific adaptations that are often linked to a species' genome size and chromosome number. Therefore, a positive association between genome size and geographic range is anticipated. Moreover, high cognitive ability in organisms would be favored by natural selection to cope with the dynamic conditions within large geographic ranges. Here, we tested these hypotheses in birds-the most mobile terrestrial vertebrates-and accounted for the effects of various confounding variables, such as body mass, relative brain mass, and geographic latitude. Using phylogenetic generalized least squares and phylogenetic confirmatory path analysis, we demonstrated that range size is positively associated with bird genome size but probably not with chromosome number. Moreover, relative brain mass had no effect on range size, whereas body mass had a possible weak and negative effect, and range size was larger at higher geographic latitudes. However, our models did not fully explain the overall variation in range size. Hence, natural selection may impose larger genomes in birds with larger geographic ranges, although there may be additional explanations for this phenomenon.
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Affiliation(s)
- Beata Grzywacz
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Kraków, Poland
| | - Piotr Skórka
- Institute of Nature Conservation, Polish Academy of Sciences, Kraków, Poland
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10
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Ruckman SN, Jonika MM, Casola C, Blackmon H. Chromosome number evolves at equal rates in holocentric and monocentric clades. PLoS Genet 2020; 16:e1009076. [PMID: 33048946 PMCID: PMC7584213 DOI: 10.1371/journal.pgen.1009076] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/23/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Despite the fundamental role of centromeres two different types are observed across plants and animals. Monocentric chromosomes possess a single region that function as the centromere while in holocentric chromosomes centromere activity is spread across the entire chromosome. Proper segregation may fail in species with monocentric chromosomes after a fusion or fission, which may lead to chromosomes with no centromere or multiple centromeres. In contrast, species with holocentric chromosomes should still be able to safely segregate chromosomes after fusion or fission. This along with the observation of high chromosome number in some holocentric clades has led to the hypothesis that holocentricity leads to higher rates of chromosome number evolution. To test for differences in rates of chromosome number evolution between these systems, we analyzed data from 4,393 species of insects in a phylogenetic framework. We found that insect orders exhibit striking differences in rates of fissions, fusions, and polyploidy. However, across all insects we found no evidence that holocentric clades have higher rates of fissions, fusions, or polyploidy than monocentric clades. Our results suggest that holocentricity alone does not lead to higher rates of chromosome number changes. Instead, we suggest that other co-evolving traits must explain striking differences between clades.
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Affiliation(s)
- Sarah N. Ruckman
- Department of Biology, Texas A&M University, Texas, United States of America
- Ecology and Evolutionary Biology Interdisciplinary Program, Texas A&M University, Texas, United States of America
| | - Michelle M. Jonika
- Department of Biology, Texas A&M University, Texas, United States of America
- Genetics Interdisciplinary Program, Texas A&M University, Texas, United States of America
| | - Claudio Casola
- Ecology and Evolutionary Biology Interdisciplinary Program, Texas A&M University, Texas, United States of America
- Genetics Interdisciplinary Program, Texas A&M University, Texas, United States of America
- Department of Ecology and Conservation Biology, Texas A&M, Texas, United States of America
| | - Heath Blackmon
- Department of Biology, Texas A&M University, Texas, United States of America
- Ecology and Evolutionary Biology Interdisciplinary Program, Texas A&M University, Texas, United States of America
- Genetics Interdisciplinary Program, Texas A&M University, Texas, United States of America
- * E-mail:
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11
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Lucek K, Butlin RK, Patsiou T. Secondary contact zones of closely-related Erebia butterflies overlap with narrow phenotypic and parasitic clines. J Evol Biol 2020; 33:1152-1163. [PMID: 32573833 DOI: 10.1111/jeb.13669] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/05/2020] [Accepted: 06/16/2020] [Indexed: 11/30/2022]
Abstract
Zones of secondary contact between closely related taxa are a common legacy of the Quaternary ice ages. Despite their abundance, the factors that keep species apart and prevent hybridization are often unknown. Here, we study a very narrow contact zone between three closely related butterfly species of the Erebia tyndarus species complex. Using genomic data, we first determined whether gene flow occurs and then assessed whether it might be hampered by differences in chromosome number between some species. We found interspecific gene flow between sibling species that differ in karyotype by one chromosome. Conversely, only F1 hybrids occurred between two species that have the same karyotype, forming a steep genomic cline. In a second step, we fitted clines to phenotypic, ecological and parasitic data to identify the factors associated with the genetic cline. We found clines for phenotypic data and the prevalence of the endosymbiont parasite Wolbachia to overlap with the genetic cline, suggesting that they might be drivers for separating the two species. Overall, our results highlight that some gene flow is possible between closely related species despite different chromosome numbers, but that other barriers restrict such gene flow.
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Affiliation(s)
- Kay Lucek
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Roger K Butlin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.,Department of Marine Sciences, Tjärnö, University of Gothenburg, Strömstad, Sweden
| | - Theofania Patsiou
- Department of Environmental Sciences, University of Basel, Basel, Switzerland.,Institute of Plant Sciences, Department of Biology, University of Bern, Bern, Switzerland
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12
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de Vos JM, Augustijnen H, Bätscher L, Lucek K. Speciation through chromosomal fusion and fission in Lepidoptera. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190539. [PMID: 32654638 DOI: 10.1098/rstb.2019.0539] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Changes in chromosome numbers may strongly affect reproductive barriers, because individuals heterozygous for distinct karyotypes are typically expected to be at least partially sterile or to show reduced recombination. Therefore, several classic speciation models are based on chromosomal changes. One import mechanism generating variation in chromosome numbers is fusion and fission of existing chromosomes, which is particularly likely in species with holocentric chromosomes, i.e. chromosomes that lack a single centromere. Holocentric chromosomes evolved repeatedly across the tree of life, including in Lepidoptera. Although changes in chromosome numbers are hypothesized to be an important driver of the spectacular diversification of Lepidoptera, comparative studies across the order are lacking. We performed the first comprehensive literature survey of karyotypes for Lepidoptera species since the 1970s and tested if, and how, chromosomal variation might affect speciation. Even though a meta-analysis of karyological differences between closely related taxa did not reveal an effect on the degree of reproductive isolation, phylogenetic diversification rate analyses across the 16 best-covered genera indicated a strong, positive association of rates of chromosome number evolution and speciation. These findings suggest a macroevolutionary impact of varying chromosome numbers in Lepidoptera and likely apply to other taxonomic groups, especially to those with holocentric chromosomes. This article is part of the theme issue 'Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.
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Affiliation(s)
- Jurriaan M de Vos
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Hannah Augustijnen
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Livio Bätscher
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Kay Lucek
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
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Warchałowska-Śliwa E, Grzywacz B, Maryańska-Nadachowska A, Heller KG, Hemp C. Rapid chromosomal evolution in the bush-cricket Gonatoxia helleri Hemp, 2016 (Orthoptera, Phaneropterinae). COMPARATIVE CYTOGENETICS 2020; 14:417-435. [PMID: 32952902 PMCID: PMC7473956 DOI: 10.3897/compcytogen.v14i3.54422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/27/2020] [Indexed: 05/03/2023]
Abstract
Gonatoxia helleri Hemp, 2016 is one of the most widespread bush-crickets of the genus Gonatoxia Karsch, 1889 in East Africa. This species with seven large chromosomes (2n♂ = 7) differs from other representatives of the genus Gonatoxia drastically by its reduced chromosome number, the asymmetrical karyotype including karyomorphs rarely found in tettigoniids, as well as in irregularities in the course of meiosis. To better understand the origin of such an exceptional karyotype, chromosomes of 29 specimens from four populations/localities were studied using classical techniques, such as C-banding, silver impregnation, fluorochrome double staining and fluorescence in situ hybridization (FISH) technique with 18S rDNA and (TTAGG) n telomeric probes. FISH showed many 18S rDNA loci as well as interstitial telomeric sequences, where chromosome morphology varied in these components in terms of quantity and distribution. The 18S rDNA loci coincided with active NORs and C-banding patterns. We suggest that a combination of Robertsonian rearrangements and/or multiple common tandem fusions involving the same chromosomes contributed to the formation of this karyotype/karyomorphs. The results are the first step towards a better understanding of chromosomal reorganization and evolution within the genus Gonatoxia. Low chromosome number, together with the incidence of chromosomal polymorphism that is higher in G. helleri than previously reported in bush-crickets, implies that this species can be a valuable new model for cytogenetic and speciation studies. Our findings suggest that chromosomal translocations lead to diversification and speciation in this species and could be the driving force of adaptive radiation.
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Affiliation(s)
- Elżbieta Warchałowska-Śliwa
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, PolandPolish Academy of SciencesKrakówPoland
| | - Beata Grzywacz
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, PolandPolish Academy of SciencesKrakówPoland
| | - Anna Maryańska-Nadachowska
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, PolandPolish Academy of SciencesKrakówPoland
| | | | - Claudia Hemp
- University of Bayreuth, Dept. Plant Systematics, Bayreuth, GermanyUniversity of BayreuthBayreuthGermany
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Lucek K, Hohmann N, Willi Y. Postglacial ecotype formation under outcrossing and self-fertilization in Arabidopsis lyrata. Mol Ecol 2019; 28:1043-1055. [PMID: 30719799 DOI: 10.1111/mec.15035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/18/2019] [Accepted: 01/28/2019] [Indexed: 12/01/2022]
Abstract
The formation of ecotypes has been invoked as an important driver of postglacial biodiversity, because many species colonized heterogeneous habitats and experienced divergent selection. Ecotype formation has been predominantly studied in outcrossing taxa, while far less attention has been paid to the implications of mating system shifts. Here, we addressed whether substrate-related ecotypes exist in selfing and outcrossing populations of Arabidopsis lyrata subsp. lyrata and whether the genomic footprint differs between mating systems. The North American subspecies colonized both rocky and sandy habitats during postglacial range expansion and shifted the mating system from predominantly outcrossing to predominantly selfing in a number of regions. We performed an association study on pooled whole-genome sequence data of 20 selfing or outcrossing populations, which suggested genes involved in adaptation to substrate. Motivated by enriched gene ontology terms, we compared root growth between plants from the two substrates in a common environment and found that plants originating from sand grew roots faster and produced more side roots, independent of mating system. Furthermore, single nucleotide polymorphisms associated with substrate-related ecotypes were more clustered among selfing populations. Our study provides evidence for substrate-related ecotypes in A. lyrata and divergence in the genomic footprint between mating systems. The latter is the likely result of selfing populations having experienced divergent selection on larger genomic regions due to higher genome-wide linkage disequilibrium.
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Affiliation(s)
- Kay Lucek
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Nora Hohmann
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Yvonne Willi
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
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